A functional murmur (innocent murmur, physiologic murmur) is a heart murmur that is primarily due to physiologic conditions outside the heart, as opposed to structural defects in the heart itself. Serious conditions can arise even in the absence of a primary heart defect, and it is possible for peripheral conditions to generate abnormalities in the heart. Therefore, caution should be applied to use of the terms "innocent" or "benign" in this context.Use of the term dates to the mid 19th century.

Benign pediatric heart murmur

Functional murmurs are an important consideration in the precordial examination of an infant or child.

Presentation

*Soft, less than 3/6 in intensity (although note that even when structural heart disease is present, intensity does not predict severity.) *Often position-dependent. Murmurs heard while supine and may disappear when upright or sitting.Thomas Biancaniello
Innocent Murmurs
'' Circulation''. 2005; 111: e20-e22. *Otherwise healthy individual, no concerns about growth, no symptoms of

heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome caused by an impairment in the heart's ability to Cardiac cycle, fill with and pump blood. Although symptoms vary based on which side of the heart is affected, HF ...

such as dyspnea on exertion. (In infants, ask if the baby cries during feeding, becomes diaphoretic, or develops a rapid respiratory rate. In older children, this can be elucidated by asking whether or not the child can keep up with peers during play.) *Occurs during systole or continuously during both systole and diastole. (Murmurs occurring only during diastole are usually pathologic, but can also be heard during hyperdynamic states.) *Physiologic splitting of S2 (A2 and P2 components should only be resolvable during inspiration and should merge during expiration.) *No palpable thrill (A thrill is a vibration caused by turbulent blood flow.)

Diagnosis

Types, and DDx

In the adult, hyperdynamic circulation of the blood may also produce a functional murmur, such as in

anemia Anemia (also spelt anaemia in British English) is a blood disorder in which the blood has a reduced ability to carry oxygen. This can be due to a lower than normal number of red blood cells, a reduction in the amount of hemoglobin availabl ...

or thyrotoxicosis.

Prognosis

Innocent murmurs are inconsequential and usually disappear as the

child A child () is a human being between the stages of childbirth, birth and puberty, or between the Development of the human body, developmental period of infancy and puberty. The term may also refer to an unborn human being. In English-speaking ...

grows. ECG and Chest XRAY are normal.

References

:6. Circulation 2005: Innocent Murmurs http://circ.ahajournals.org/cgi/content/full/111/3/e20

External links

Heart Murmurs in Pediatric Patients: When Do You Refer?
- AAFP {{Circulatory and respiratory system symptoms and signs Heart murmurs Pediatrics